The present invention relates to a yarn beam flange or a yarn limiting disc device for use in winding a yarn package on a yarn package carrier such as a loom beam, a warp beam, a weaver beam or a sectional beam of a textile machine. More particularly, the present invention is directed to such a device of the type including a generally flat disc body adapted to have extend therethrough a beam of a yarn package carrier onto which a yarn package is to be wound, with one side of the disc body being equipped with generally radially extending strengthening or reinforcing ribs. Such type of device is disclosed in West German DE-GM No. 1,978,197.
However, such known devices suffer from certain inherent disadvantages. For example, the considerable compressive forces generated during the winding of plastic yarns or yarns mixed with plastic act on the yarn flange or yarn limiting disc device and cause a bending stress thereto. This stress must be absorbed by the device with minimum deformation and be transmitted to the yarn beam extending through the device. This is led to a large variety of types of constructions, the aim of which always is to minimize the net weight of the device with maximum loading capacity and, thereby a maximum utilization of the material of the device. The load on the disc device is not even over the entire surface of the device radially, but increases constantly from the outer edge or periphery to the inner edge or periphery of the device. Thus, the radially inner area of the disc device may be subjected to yarn pressure per unit area up to three times that at the radially outer area of the disc device. This at least partially is due to the fact that the yarn forces of the yarn package act not only axially, but also radially, and the radial forces increase with the yarn package winding operation. These forces include axial and radial forces, thereby increasing the axial load at the inner area of the disc device.
The yarn limiting disc device in the past has been provided with external reinforcements to absorb all of these forces. This however has required a very strong and solid structure, both of the planar disc body and of reinforcements in the form of ribs and strips in order to maintain a satisfactory section modulus or moment of resistance. This however has resulted in a heavy net weight of the disc device with unfavorable material utilization. The dimensions grow significantly with increasing disc cross section, because the forces exerted by the yarn increase correspondingly as a result of increased quantities of yarn being wound, such quantities increasing by a factor of the square of the cross section of the disc. Consequently, due to the fact that the axial height of the disc device generally is limited or fixed, the suction modulus or moment of resistance of increased size disc devices will not be sufficient to absorb the resultant forces.
In addition, although it is necessary to accept a slight deformation of the disc device, the extent of bending or deformation of the disc device must not be of an amount to allow the outermost yarn layers to slide or slough off the wound yarn package over the disc device, since otherwise the entire yarn package would have to be rejected.
In known constructions of yarn limiting disc devices, the reinforcing ribs are solid. It further is known, such as disclosed in Swiss Pat. No. 606,546, to provide the solid reinforcing ribs in the interior of a cavity formed by a double-wall warp beam disc body. However, even this type of structure has proved to have only limited strength.